[OYPD-468] Add abilty to stop the contious scroll of the slides in the gallery.

[ivan-berezhnov]

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General checks

• All coding styles are fulfilled and there are no any issues reported by CodeSniffer CI.
  
• All tests are running and there are no failed tests reported by CI.
  
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Thank you for your contribution!

Jira issue:

https://propeople-us.atlassian.net/browse/OYPD-468
Drupal.org issue: https://www.drupal.org/node/2885456

Steps to review:

• Go to [sitename]/accelerator
• Click "tab" on the keyboard
• When you have focused on the Left Arrow or Right
• Verify slider is stopped
• Click "tab" on the keyboard again and unfocus the Left Arrow or Right
• move mouse cursor on the gallery or the Left Arrow or Right buttons
• Verify slider is stopped

[gundevel]

Build comment file:

===============

Environment	Link
Fresh OpenY installation	http://ci.openymca.org/build1523
Upgraded(upgrade path) installation	http://upgrade.openy-dev.ffwua.com/build1523
Installation process	http://install.openy-dev.ffwua.com/build1523/install.php

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Test PASSed.
Refer to this link for build results (access rights to CI server needed):
http://ci.openymca.org:8080/job/PR_BUILDER/1523/

[gundevel]

Behat test results file URL: http://ci.openymca.org/build1523/profiles/contrib/openy/build/reports/behat